The conventional carbothermic Advanced Reactor Process is a multi-stage system in which a molten slag bath containing alumina and carbon is reacted to produce aluminum carbide in a low temperature stage. The resulting alumina-aluminum carbide slag then flows into a high temperature stage where the aluminum carbide is reacted with the alumina to produce aluminum metal. The aluminum is less dense than the slag and accumulates as a layer floating on the slag. The low temperature and high temperature stages are located in a common reaction vessel and are separated by an underflow partition wall. The high temperature stage has an outlet for continuously tapping molten aluminum. Additional carbon material is supplied to the high temperature stage to satisfy the reaction stoichiometry.
Energy required for the low temperature stage melting and pre-reduction is supplied by high intensity slag resistance heating using vertical carbonaceous electrodes submerged in the molten slag. Similarly, energy to the high temperature stage is high intensity slag resistance heating via a plurality of pairs of horizontally arranged electrodes through the sidewall of the reactor into the slag phase and below the metal phase.